Recently, a GaN-based compound semiconductor has become a focus of attention as a semiconductor material of a short-wavelength light emitting element. The GaN-based compound semiconductor is formed by a metal organic chemical vapor deposition method (MOCVD method), a molecular beam epitaxy method (MBE method) or the like on a sapphire single crystal or other various oxides or group III-V compounds provided as a substrate.
In a semiconductor light emitting element using the GaN-based compound semiconductor, a laminated semiconductor layer having a light emitting diode (LED) structure constituted by an n-type semiconductor layer, a light emitting layer and a p-type semiconductor layer is formed on a substrate and an electrode having optical transparency (transparent electrode) is formed on the p-type semiconductor layer on the top portion, thereby extracting emitted light via the transparent electrode. In such a semiconductor light emitting element, it is necessary to set a current distribution to be uniform so that an unevenness of light emission intensity does not occur.
For example, in the Patent Literature 1, a semiconductor light emitting element that includes a semiconductor layer in a rectangular parallelepiped shape having a first conductivity type gallium nitride-based compound semiconductor layer, a light emission layer made of a gallium nitride-based compound semiconductor, and a second conductivity type gallium nitride-based compound semiconductor layer, those layers being formed in order on a top surface of a substrate; a first conductivity type electrode formed on a surface of the first conductivity type gallium nitride-based compound semiconductor layer; and a second conductivity type electrode formed on a surface of the second conductivity type gallium nitride-based compound semiconductor layer is disclosed. In the semiconductor light emitting element, the first conductivity type electrode and second conductivity type electrode are formed such that one electrode is in a polygonal annular shape to enclose the other electrode and internal edges of corners of the polygonal annular shape are formed in curved shapes in a planar view, thereby deviations in current density and current distribution are reduced.